Multiple pedestal furnace installation

ABSTRACT

A furnace structure and multiple pedestal base installation for heat treating stacked coils of strip material. The pedestals are insulation lined to support the coils, and are supported above the working floor. An elastimeric seal is provided around each pedestal for the reception of a bell inner cover. The furnace structure has support means defining a furnace which has insulation lining substantially totally enclosing the top and sides thereof and defining the bottom with openings therein for reception of the bell covers therethrough. Heating means are carried by the interior of the furnace, but the bottom insulation protects the seals and bottom of the bell covers cooperating with the seals from direct radiation therefrom.

United States Patent [1 1 Blackman Jan. 1,1974

[ MULTIPLE PEDESTAL FURNACE INSTALLATION [22] Filed: May 22, 1972 [21]Appl. No.: 255,785

Primary Examiner-John J. Camby Att0 rney-William N. Hogg [5 7] ABSTRACTA furnace structure and multiple pedestal base installation for heattreating stacked coils of strip material. The pedestals are insulationlined to support the coils, and are supported above the working floor.An elastimeric seal is provided around each pedestal for the receptionof a bell inner cover. The furnace structure has support means defininga furnace which has insulation lining substantially totally enclosingthe top and sides thereof and defining the bottom with openings thereinfor reception of the bell covers therethrough. Heating means are carriedby the interior of the furnace, but the bottom insulation protects theseals and bottom of the bell covers cooperating with the seals fromdirect radiation therefrom.

9 Claims, 4 Drawing Figures MULTIPLE PEDESTAL FURNACE INSTALLATIONBACKGROUND OF THE INVENTION This invention relates generally to heattreating devices, and more particularly to multiple pedestal belltypeheat treating installations in which a removable outer furnace isemployed.

The use of multiple pedestal bell-type heat treating installations is awell known well accepted practice in the art of heat treating coils ofstrip material, such as coiled steel strip. Conventionally suchinstallations include a plurality of pedestals having insulation andcharge support means thereon for the reception of stacked coils ofmaterial. A seal, normally a sand seal, is provided around eachpedestal, and bell-type inner covers are provided for each pedestal,each adapted to be in place over a stack of coils with the lower rimthereof sealing in the sand seal around a respective pedestal. Firebrickor other heat insulation surrounds and fills the space between each ofthe pedestals. An open bottom insulation lined furnace is then placedover the bell inner covers to provide the heat source.

The furnace is heated until the desired temperature is obtained and heldfor the prescribed period. The furnace is then removed for the coolingcycle. Such an installation is shown in U.S. Pat. No. 3,497,193 datedFeb. 24, 1970, entitled Multi-Pedestal Bell-Type Annealing Furnace.

These types of multiple pedestal bases have performed quite well wherevolume and output of heat treatment warrants their installation.However, they do have certain drawbacks which impair their efficiencyand somewhat limit their usage. One of these drawbacks is the largeamount of insulation required on each base around the pedestal beneaththe furnace. This results in a substantial added expense requiring thisinsulation on all of the bases. Also, this insulation has to be heatedeach time the furnace is heated, thus requiring additional fuel andtime. Also, this insulation limits the amount of working floor spacearound the pedestals making much of it unavailable to set down the bellinner covers when they have been removed.

Also, because of their location, the seals around each pedestals havenecessarily conventionally been sand seals which is undesirable forseveral reasons. First, it is necessary to keep the sand away from thecoils being heat treated since the sand can produce unwanted surfacedefects in subsequent rolling operations. Also, sand seals must becarefully and frequently cared for to maintain proper sealingefficiency. Also, with sand seals it is not practicable or often noteven possible to provide a water spray on the bell inner covers duringthe cooling cycle to increase the cooling rate.

SUMMARY OF THE PRESENT INVENTION According to the present invention afurnace structure and base therefore are provided wherein a plurality ofpedestals for supporting coiled material are mounted on the floor orother load bearing structure. The pedestals have charge support means tosupport the coils. The furnace has structural support means defining afurnace shell enclosure for removable placement overlying andsurrounding the pedestals with the bell covers in place thereon. Furnaceinsulating material is carried by the support means internally thereofwith the insulating material substantially totally enclosing the sidesand top of the furnace and being disposed to define a bottom thereofwith openings conforming in shape to and positioned and dimensioned toreceive the bell ,covers therethrough and being of a size tosubstantially totally enclose around the covers when the covers are inplace on the pedestal. This structure eliminates the necessity of havinginsulation around the pedestals. the insulation being maintained withinthe furnace. This means that the base need not have this insulationlining, the lining being only necessary for the number of furnaces,which is substantially less than the number of bases. Also, the bottominsulation, being contained within the furnace, maintains its heat asdoes the other insulation in the furnace so that there is less heatloss. Further, this structure allows the inner cover seals to be locatedso that they are protected from direct heating and therefore permits theuse of solid or other non sand seals.

DESCRIPTION OF THE FIGURES FIG. 1 is a plan view partially in section ofa furnace in place over a four pedestal base according to thisinvention;

FIG. 2 is a side elevational view partially in section of the structureof FIG. 1;

FIG. 3 is a sectional view taken substantially along the planedesignated by the line 33 of FIG. I; and

FIG. 4 is a perspective view somewhat diagramatic of the furnace beingplaced over bell covers supported by the base.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing, afurnace structure and associated base structure according to thisinvention are shown. The invention is described in conjunction with afour pedestal base; however, it will be un derstood that it is equallyapplicable to any number of multiple pedestal bell-type annealingfurnace installations.

In the preferred embodiment four pedestals designated generally as 10are provided which are defined by structural support members 12 mountedon I beams 14 supported on a working floor 15. Each structural supportmember 12 is provided with insulation 16 with a charge support structure17 positioned to support the coiled strip of material C thereon. Thestructural support member 12 of the base also defines an annular channel18 thereon. At the bottom of the channel 18 is an annular elastimericseal 20 formed of natural or synthetic rubber or other suitableelastimeric material. The annular channel 18 is in part defined by anouter upstanding steel ring 22 through which extends a discharge pipe24.

A conventional fan motor 26 is secured to the base to drive a fan (notshown), the fan motor 26 extending into an access pit shown at 28.

Bell-type inner covers designated generally as 32 are provided foreachof the bases and are adapted to overlie the stacked coils C on the basesto enclose the coils therein for proper atmosphere control. Each of thebell covers 32 includes a cylindrical side shell and top domed portion34 which covers the coils and a sealing band 36 disposed around thelower rim thereof. The sealing band 36 has a hollow interior 38 for thereception of cooling fluid and a lower surface 40 which is adapted torest on and thereby seal against the seal 20.

A water inlet pipe 42 supplies cooling water to the interior 38 of theband 36. The inlet pipe 42 has a quick disconnect coupling 44 adapted toconnect to a water supply 46. The inlet pipe 42 is positioned so that itwill extend through a slot 48 provided in the outer ring 22 when thebell cover is properly positioned. The sealing band 36 also has anoutlet opening 50 to provide for the discharge of cooling water.

Thus when the bell cover 32 is in place, the sealing area thereof can bewater cooled by providing water to the interior 38 thereof through theinlet pipe 42, the water being discharged through the outlet 50 into thechannel 18 from which it will discharge through discharge pipe 24. Thebell-type covers 32 are provided with conventional lifting lugs 52 toallow for them to be removed and placed properly.

A removable furnace structure 56 is provided for removable placementover the pedestals with the bell covers 32 thereon. The furnacestructure includes a steel top plate 58, steel side plates 60, steel endplates 62, and a steel bottom plate 64, which plates together definestructural support shell. The top, side and end plates are solid,whereas the bottom plate 64 is provided with a series of four apertures66, each being of a size and configuration to surround a bell innercover when positioned on a pedestal 10 when the furnace is in place. Theinterior of the plates is lined with insulation 68 with the lining onthe bottom plate 64 having apertures 70 corresponding in size and shapeto the apertures 66 and the steel bottom plates 64. Thus when thefurnace structure 56 is in place over the pedestals and over the bellcovers, the bottom plate 64 thereof will rest on the outer ring 22 ofeach of the pedestals 10 providing structural support therefor.

A plurality of burners 72 are provided in each of the side plates 60,the burners being supplied by manifolds 74 which are adapted to beconnected to a source of fuel supply. These manifolds are shown onlydiagramatically, their specific construction not being a part per se ofthe present invention. Also, it is to be understood that electricheating means, radiant tubes, or other heat sources could also beemployed rather than burners. It will be noted that with the furnacestructure in place the insulation 68 on the bottom plate 64 of thefurnace extends inwardly toward the bell cover 32 providing an annularshielding surface 75 at a location between the burners 72 and the seal20. Thus the seal is protected from direct radiation from the burnersand the radiation furnace side walls. This protection, together with thecooling of the sealing band 36 where required, provides adequateprotection so that solid elastimeric seals or liquid or other lowtemperature seals can be utilized in place of more conventional sandseals.

In order to guide the furnace structure 56 into place properly a pair ofguide posts 76 are provided which are secured to the working floor andextend upwardly therefrom. These guide posts are positioned to cooperatewith a pair of guide collars 78, one of which is located on each of theside plates 60 and which are located to slidably engage the guide posts76 to accurately guide the furnace into position as it is being lowered(as shown in FIG. 4) into position. The furnace structure 56 is raisedand lowered by means of a conventional lifting eye 80 mounted on the topplate 58 and located to be engaged by a crane hook as shown in FIG. 4.

Thus it can be seen that with a furnace structure and base constructedaccording to this invention a plurality of pedestals are provided whichhave insulation thereon but which do not require insulation therearoundbetween the pedestals, thereby providing working area immediatelyadjacent the pedestal. The insulation lining on the bottom of thefurnace provides the necessary insulation during heating, and when thefurnace is removed it is not necessary to wait for insulationsurrounding the furnace to cool before working therearound. Further, theheat required to heat the firebrick is not wasted, since this heat isretained within the furnace, which furnace, in the majority of thecases, is used immediately on another base so that the retained heat isactually utilized in a subsequent heating operation. Also, one furnacecan serve several base installations, thus not requiring amultiplication of the amount of insulation required as is the case wheneach base is insulated.

It will further be noted that this construction of the furnace with theinsulation on the bottom allows a solid seal to be used in place ofconventional sand seals. This removes one of the major undesirablefeatures of prior art conventional multiple stack base installations. Byutilizing the solid seal in place of sand the danger of sandcontaminating the coils thus is eliminated. Further, when this type ofseal in the furnace structure has been removed, cooling water spray canbe directed against the bell-type covers to assist in the cooling withthe channel 18 collecting and disposing of the water which may drain offthe inner covers.

Thus an improved multiple pedestal bell-type furnace installation isprovided which retains the desirable features of the prior art butovercomes many of the drawbacks and limitations thereof.

What is claimed is:

1. A furnace structure for an annealing furnace assembly, wherein aplurality of pedestals for supporting coiled material are provided, andwherein each pedestal has associated therewith a seal for the receptionof a bell-type cover,

said furnace structure comprising,

structural support shell defining a movable furnace enclosure forremovable placement overlying and surrounding the pedestals with bellcovers in place thereon, insulating material carried by said supportmeans internally thereof, said insulating material substantially totallyenclosing the sides and top of said furnace structure and being disposedto define a bottom thereof with means forming individual spaced openingsconforming in shape to and positioned and dimensioned to receive thebell covers individually therethrough and being of a size tosubstantially totally enclose around said covers when said covers are inplace on the pedestals, and heating means carried internally of saidfurnace structure.

2. The invention as defined in claim 1 wherein the bottom of saidfurnace structure is positioned and shaped to shield the seals fromdirect heat radiation from said heating means.

3. The invention as defined in claim 1 further characterized by guidemeans to guide said furnace structure into place over said bell covers.

4. The invention as defined in claim 3 wherein said guide means includescooperating post means and collar means.

5. An annealing furnace assembly comprising, a pluenclose around saidcovers when said covers are in rality of pedestals mounted on astructural support, place in the pedestals, and heating means carriedeach pedestal having means for supporting coiled mateinternally of saidfurnace structure. rial, a seal surrounding each pedestal for thereception 6. The invention as defined in claim 5 wherein the of a belltype cover, 5 bottom of said furnace structure is positioned to shieldstructural support shell defining a movable furnace the seals fromdirect heat radiation from said heating enclosure for removableplacement overlying and means. surrounding the pedestals with bellcovers in place 7. The invention as defined in claim 6 wherein thethereon, insulating material substantially totally enseals are solidseals. closing the sides and top of said furnace structure 10 8. Theinvention as defined in claim 6 wherein liquid and being disposed todefine a bottom thereof with cooling means for the seals are provided.means forming individual spaced openings con- 9. The invention asdefined in claim 5 further characforming in shape to and positioned anddimenterized by trough means around each of said pedestals sioned toreceive the bell covers individually therefor the collection of water.through and being of a size to substantially totally 5

1. A furnace structure for an annealing furnace assembly, wherein aplurality of pedestals for supporting coiled material are provided, andwherein each pedestal has associated therewith a seal for the receptionof a bell-type cover, said furnace structure comprising, structuralsupport shell defining a movable furnace enclosure for removableplacement overlying and surrounding the pedestals with bell covers inplace thereon, insulating material carried by said support meansinternally thereof, said insulating material substantially totallyenclosing the sides and top of said furnace structure and being disposedto define a bottom thereof with means forming individual spaced openingsconforming in shape to and positioned and dimensioned to receive thebell covers individually therethrough and being of a size tosubstantially totally enclose around said covers when said covers are inplace on the pedestals, and heating means carried internally of saidfurnace structure.
 2. The invention as defined in claim 1 wherein thebottom of said furnace structure is positioned and shaped to shield theseals from direct heat radiation from said heating means.
 3. Theinvention as defined in claim 1 further characterized by guide means toguide said furnace structure into place over said bell covers.
 4. Theinvention as defined in claim 3 wherein said guide means includescooperating post means and collar means.
 5. An annealing furnaceassembly comprising, a plurality of pedestals mounted on a structuralsupport, each pedestal having means for supporting coiled material, aseal surrounding each pedestal for the reception of a bell type cover,structural support shell defining a movable furnace enclosure forremovable placement overlying and surrounding the pedestals with bellcovers in place thereon, insulating material substantially totallyenclosing the sides and top of said furnace structure and being disposedto define a bottom thereof with means forming individual spaced openingsconforming in shape to and positioned and dimensioned to receive thebell covers individually therethrough and being of a size tosubstantially totally enclose around said covers when said covers are inplace in the pedestals, and heating means carried internally of saidfurnace structure.
 6. The invention as defined in claim 5 wherein thebottom of said furnace structure is positioned to shield the seals fromdirect heat radiation from said heating means.
 7. The invention asdefined in claim 6 wherein the seals are solid seals.
 8. The inventionas defined in claim 6 wherein liquid cooling means for the seals areprovided.
 9. The invention as defined in claim 5 further characterizedby trough means around each of said pedestals for the collection ofwater.